8 This is the park switch, which terminates the motor’s ground when the wipers park. When wipers are turned on, your switch grounds the wiper motor, which starts wiper operation. As long as the wiper switch is on, the motor has a ground and continues to operate. When you turn the switch off, this breaks the switch ground, which leaves the park switch as the sole ground. When wipers reach park position, the parking cam and link open the park switch, which terminates that ground and stops the wipers.